For information about the SORT evidence rating system, go to https://org/Pneumonia and influenza combined is the eighth leading cause of death in the United States and the most common cause of infection-related mortality.5 In 2007, about 52,700 persons died from the conditions.5 The overall annual incidence of CAP ranges from five to 11 per 1,000 persons, with more cases occurring in the winter months.1 In 2006, there were approximately 4.2 million ambulatory care visits for CAP in the United States, with species, and respiratory viruses.Overall, physician judgment is moderately accurate for diagnosis of pneumonia, especially for ruling it out (LR = 2.0, negative likelihood ratio [LR–] = 0.24).7 Absence of fever and sputum also significantly reduces the likelihood of pneumonia in outpatients.8High fever (greater than 104° F [40° C]), male sex, multilobar involvement, and gastrointestinal and neurologic abnormalities have been associated with CAP caused by infection.9 The clinical presentation of CAP is often more subtle in older patients, and many of these patients do not exhibit classic symptoms.1 They often present with weakness and decline in functional and mental status.The patient history should focus on detecting symptoms consistent with CAP, underlying defects in host defenses, and possible exposure to specific pathogens.However, it is often not possible to distinguish typical versus atypical pneumonia solely on clinical grounds.Common symptoms include fever (positive likelihood ratio [LR ] = 4.5), chills, pleuritic chest pain, and a cough producing mucopurulent sputum.Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults Hypoglycemia (blood glucose level less than 70 mg per d L [3.89 mmol per L]) at presentation is associated with increased 30-day mortality even after adjustment for other variables, including comorbid illness and Pneumonia Severity Index (PSI) score.15 Procalcitonin levels are elevated in many patients with bacterial infections, and several studies have shown procalcitonin tests to be potentially useful in CAP.16 per L; LR = 3.4, LR– = 0.52) and a C-reactive protein level of 5.0 mg per d L (47.62 nmol per L) or greater (LR = 3.1, LR– = 0.7) are modestly helpful when positive, but it is important to note that normal values do not rule out pneumonia.18Blood cultures are not recommended for most hospitalized patients with CAP and should be performed according to the recommendations in .
A study comparing 125 patients with CAP caused by pneumococcal bacteremia and 1,847 patients with nonbacteremic CAP found no increase in poor outcomes among those with bacteremia.19 In addition, false-positive blood culture results have been associated with prolonged hospitalization and more vancomycin use.20 Blood cultures should be ordered for patients with severe CAP Any major criterion is an absolute indication for admission to an intensive care unit.
Evaluation for specific pathogens that would alter standard empiric therapy should be performed when the presence of such pathogens is suspected on the basis of clinical and epidemiologic clues; this testing usually is not required in outpatients.
A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, usual practice, expert opinion, or case series.
Patients with severe community-acquired pneumonia or who are admitted to the intensive care unit should be treated with a beta-lactam antibiotic, plus azithromycin or a respiratory fluoroquinolone.
Those with risk factors for should be treated with a beta-lactam antibiotic (piperacillin/tazobactam, imipenem/cilastatin, meropenem, doripenem, or cefepime), plus an aminoglycoside and azithromycin or an antipseudomonal fluoroquinolone (levofloxacin or ciprofloxacin).
For outpatients with comorbidities or who have used antibiotics within the previous three months, a respiratory fluoroquinolone (levofloxacin, gemifloxacin, or moxifloxacin), or an oral beta-lactam antibiotic plus a macrolide should be used.